Posted: 2012.01.24(Tue)17:53 Post subject: How often to change light bulbs?

Hi,
I have a coralife 96 watt fixture and I've never changed the bulb for the past 3+ years. I have a moderately planted tank. How often should I change the bulb?? I heard that changing it more frequently will increase plant growth. Is this true? Thanks!

Yup... it is true. Most light bulbs should be changed every six months to a year. You might want to do a google search for your specific light bulb to see what is recommended for it._________________135 gln. freshwater tank
29 gln. freshwater tank

Yes the light strength on standard fluorescents gets reduced after 6mo-year. Not sure about CFL bulbs, however. If you just want to see the fish you can probably keep it going until it burns out but the plants won't grow as well.

Most high quality linear flourescent bulbs should only decay 5-10% in lumen output after the full life of the bulb (years!) & frankly I see no point in replacing these every year. Should be able to run them until they die with no issues about fading intensity. Not sure where this 6 months to a year replacement thing comes from, might have been the case with older bulbs? Someone have a link to some hard data on this?

I think CFL bulbs are more prone to fading out than regular flourescents - need to check the manufacturer spec sheet for your particular bulb, it should specify life and decay of the bulb._________________Fishing in the Rivers of Light

But most people don't buy "high quality linear flourescent bulbs" or quality units themselves. I change mine every year, my 108w 48" T5HO unit cost 96$ the bulbs 15$ a piece. So I am OK with changing them once a year. Compare that to some of the other T5 fixtures and I paid a 3rd of the cost.

I used to think that way but you'd be surprised - all the tubes from major lighting companies e.g. Phillips, GE, so on have very good lumen maintainence. These are the type of stuff you'd buy at the hardware store. Funnily enough, it's the expensive aquarium specific bulbs that don't seem to give these specs, which makes me wonder sometimes.

I'd be pretty surprised if any fluorescent fixture was really different in terms of "quality" - and by this I mean by the ballast specs as this is about the only thing that really affects bulb life. Reflectors, outer shell etc all vary a lot, but they all tend to run e-ballasts now. Don't even know if the old magnetic ballasts are still manufactured anymore._________________Fishing in the Rivers of Light

Here's one of several articles I found talking about the bulb life. Most of the articles were specifically about marine tanks and their lighting issues but this one talks about fluorescent bulbs that many of us use.

I think the quality of the bulb is always a factor in how long it really gives the proper intensity for planted tanks. I do know that I have always seen a sudden growth spurt in my tanks after changing bulbs. So something is making a difference._________________135 gln. freshwater tank
29 gln. freshwater tank

Here's one of several articles I found talking about the bulb life. Most of the articles were specifically about marine tanks and their lighting issues but this one talks about fluorescent bulbs that many of us use.